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Chemistry Unit 1
Chapter 1
WHMIS and Safety
The lab can be a very dangerous place, so there must be a common set of guidelines that are
followed by all. Not only do we need a universal set of safety rules but the labeling we use must
be understandable by everyone regardless of language. This system is used for mainly industrial
locations, not household use.
Workplace
Hazardous
Materials
Information
System
Is the international system for labeling hazards. There are a number of symbols, 1 for each
hazard class.
Class A Compressed gas:
This symbol is for any container that has gas under
pressure. A propane tank is a good example of something that would have this symbol.
Class B Flammable and combustible material:
This symbol is for materials that can
easily catch fire. To go back to the propane tank, the propane gas itself would have this class.
So a tank of propane would have both these symbols.
Class C Oxidizing material:
These materials can cause materials to burn, or burn
easier and quicker than they would normally. A tank of oxygen gas would be an example of
this, plus it would have the compressed gas symbol as well.
Class D1 Poisonous materials causing immediate and serious toxic effects:
These are
so toxic that they can cause coma or death in minutes or hours. Carbon Monoxide is a common
example of this.
Class D2 Materials causing other toxic effects:
These are not as quick or if they are
quick then the effect is not permanent. They can still cause cancer, allergies, reproductive
problems or harm a fetus. Mercury and Lead are good examples.
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Class D3 Biohazardous infectious material:
This is for organisms such as bacteria,
viruses, fungi and parasites that can cause disease. Since they live in body tissues or fluids, we
treat all tissues or fluids as biohazardous. HIV virus or Hepatitis B are in this group.
Class E Corrosive material:
These materials can cause burns to skin and other
tissues, can attack cloths and even metals. Acids such as sulphuric acid and Bases like
ammonium hydroxide are in this category.
Class F Dangerously reactive material:
These can either react vigorously with water to
produce a toxic gas, react with itself if bumped or dropped. It is basically "unstable". Picric acid
is a classic example of this. Last year the St. Clairs hospital was closed down so that this
chemical could be removed.
There are also another set of symbols that are for household use. The symbol tells you the
danger and the shape of the symbol tells us how dangerous it is. The more sides it has the
more dangerous it is.
Science Lab Safety PowerPoint
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Matter
Matter is anything that has mass and takes up space. Mass is often measured in grams and
volume is often measured in liters.
Physical Properties of matter
These are characteristics of a type of matter that you can determine by observing the substance
and testing it by itself.
Physical Property
Description
Qualitative
State
Solid, liquid, gas
Colour
Colour
Malleability
Ability to be bent or beaten into sheets
Ductility
Ability to be drawn into wires
Texture
Appearance and feel of the surface
Magnetism
Tendency to be attracted to a magnet
Lustre
Degree to which the material reflects light
Quantitative
Solubility
Ability to dissolve in water
Conductivity
Ability to conduct electricity or heat
Viscosity
Resistance to flow
Density
Ratio of a material’s mass to its volume
Melting point
Temperature of melting/freezing
Boiling point
Temperature of boiling/condensing
Chemical Properties of matter
These are characteristics that you can only determine when your substance interacts with other
substances.
Chemical Property
Description
Reactivity
Degree to which the substance combines chemically with other
substances (water, acid, other substances)
Combustibility
Degree to which the substance burns (reacts with air or pure
oxygen)
Toxicity
Degree to which the substance reacts in the body to produce
harmful substances
Law and Theory
A theory is the best explanation that we can think of. There are observations that cannot be
explained by the theory but it is the best explanation we have so far.
A law explains all observations and perfectly predicts the outcome of an experiment. There are
no exceptions to the rules in a law.
The theories below are just that, theories. They show the progression of science just like the
models of the solar system.
Atomic Theory
1) First theories: Some said that the world was made up of a few elements. Earth, Air, Fire,
Water in different amounts. Others reasoned that if you cut up anything, the pieces get
smaller. Eventually you can’t cut them up any smaller. This uncuttable piece was canned
ATOMOS, which is where the word Atom comes from today.
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2) Middle Ages Theories: Man was driven to try to change common metals like Lead into Gold.
As they studied and tried in vain to do this, they gained a better understanding of matter and
began to get rid of the 4 elements theory. Many believed in Alchemy (like a basic chemistry
searching to find out how to change substances ‘magically’) and were looking for a magical
substance like Harry Potter’s "Philosopher Stone" .
3) John Dalton (1766-1844): Developed the first "modern" theory of the atom. He put forth that
atoms were like solid spheres and that the atoms of each element were different. Atoms could
not be created or destroyed or divided into smaller particles. Also that compounds were of
different atoms combined in particular proportions. (Example H2O or HCl)
4) J.J Thomson (1856-1940): "The Raisin Bun" model. He discovered that electricity was a
stream of electrons and that all atoms had them. So if an atom was not just a ball but a ball
with electrons stuck in them, that sometimes can escape. This newer better theory would
explain more observations than Dalton.
5) Ernest Rutherford (1871-1937): Designed an experiment where he shot tiny particles called
alpha particles at a very thin sheet of gold. Most went straight through the sheet, but some
were deflected and a very few were bounced back. From this he could conclude that an atom
was mostly empty space and that there was a very small positive center (nucleus) and the
negative electrons orbit around it.
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6) Niels Bohr (1885-1962): Refined the Rutherford model further. Not only are the electrons
orbiting around the nucleus, but they are orbiting in specific levels. Electrons can absorb energy
and move to a higher level and emit energy and fall down to a lower level if there is space for
them in the level.
7) "Newer Theories": The Bohr model is not the newest model but the most complex model that
we learn about. There is a Quantum model which is left for university level chemistry that is a
better theory but very complex.
The Atom
All matter is made up of atoms. Atoms are made up of three different sub-particles
Subatomic particle
Charge
Mass
Proton
+1
1.67x10-27 kg
Electron
-1
9.11x10-31 kg
Neutron
Neutral
1.67x10-27
Notice that protons and neutrons are the same size and electrons are 10,000 times smaller than
the other two.
The atom is mostly empty space, like our solar system. If an atom was the size of a football
stadium then the nucleus would be at the center and the size of a grain of sand and the
electrons would be orbiting in the parking lot.
Atoms come in different arrangements of the above subatomic-particles, each arrangement is a
different element and has unique properties.
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Chapter 2
Element: Each element is a unique form of matter and has a unique number of Protons and
Electrons. Hydrogen for example has 1electron and 1 proton, Carbon has 6 electrons and 6
protons.
The Periodic Table of Elements
This is a table constructed to show the relationships between the different elements. Dmitri
Mendeleev a Russian chemistry professor invented the periodic table that we use today. Not
only did he make the table for the known elements but he also predicted using the table,
elements that were not yet discovered. Later they were discovered.
The table is organized from smallest element to largest but also keeping the elements that have
similar properties together. The elements get bigger as you go across a row (Period) but also
have the same number of electron levels. As you go down a column (Family) all the elements
have a similar arrangement of electrons in the outer level (Shell).
Lets have a look at the table and its elements so it can make more sense.
Here is a good link for studying the Periodic Table: Periodic Table
Each element has a symbol, It contains 1 or 2 letters. The first letter is always capital and the
second is always lower case. Because there are more than 26 elements we have to use at least
2 letter for each symbol. Hydrogen for example has the symbol "H" but Helium has the symbol
"He". Most symbols make sense like the ones that we just mentioned, some however do not
make sense at first look. Iron for example is "Fe" why? It was nemed a long time ago in
another language, it was called Ferrum, which now makes sense. Potassium "K" was called
kalium. Gold "Au" was called aurum. Most of the elements that do not make sense are
elements that have been known for thousands of years and are based on other languages.
Atomic Number and Atomic Mass
The atomic number of an element tells us information about it. The atomic number tells us the
number of Protons and the number of Electrons that are in an atom of a particular element. So
Carbon with an atomic number of 6 will have 6 Protons and 6 Electrons in it. Since protons are
positive and electrons are negative, atoms are neutral.
The atomic mass is the total mass of an atom of an element. It is the total mass of all the
protons, neutrons and electrons in the atom. Most elements have more than one form that have
different numbers of Neutrons, these are called Isotopes. The atomic mass number on the table
is the average of the masses of the elements isotopes. That is why it is a decimal number.
Remember...
Subatomic particle
Charge
Mass
Proton
+1
1.67x10-27 kg
Electron
-1
9.11x10-31 kg
Neutron
Neutral
1.67x10-27
Since electrons are so much lighter than the protons and neutrons, they don’t really count much
towards the total mass.
The atomic number tells us the protons and the atomic mass tells us the number of protons and
neutrons, since they are the "heavy" particles in the atom. So if you subtract the proton number
from the mass you get the number of Neutrons. Example: Iron has the symbol Fe, it has an
atomic number of 26 which means it has 26 Protons. It has an atomic mass of 55.8 (round to
56). 56-26=30, so Iron has 30 Neutrons.
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Major groupings of the periodic table
State at Room
Appearance
Temperature
Metals
• solid except for • shiny lustre
mercury (a
liquid)
Non-metals
• some gases •
• not very shiny
some solids •
only bromine is a
liquid
Metalloids
• solids
• can be shiny or
dull
Conductivity
• good conductors of
heat and electricity
Malleability
and Ductility
• malleable •
ductile
• poor conductors of
heat and electricity
• brittle • not
ductile
• may conduct
electricity • poor
conductors of heat
• brittle • not
ductile
The Metals are on the Left of the periodic table and Non-metals are on the right. They are
separated by the "staircase" in the table. The elements that are close to the staircase are called
metalloids and can have properties of either metals or nonmetals, since they are close to both.
Alkali Metals: (Column 1 but not Hydrogen) Li, Na, K, Rd, Cs, Fr. They are all soft metals that
are highly reactive. They get more reactive as you go down the family. They even react with
oxygen and water in the air and must be stored under oil.
Alkaline Earth Metals: (Column 2) Be, Mg, Ca, Sr, Ba, Ra. Less reactive than the Alkali metals
but still very reactive. If heated they burn with bright colorful flames and are used in fireworks.
Halogens: (Column 17) F, Cl, Br, I, At. Are non-metals and are highly reactive. F and Cl are
gases at room temp, Br is a liquid and I is a solid.
Noble Gases: (Column 18) He, Ne, Kr, Xe, Rn. These are stable and unreactive gases. (The
‘nobles’ did not interact with the regular people—get it?) Neon and Argon are used in some
lights, Helium is lighter than air and is used in balloons. Noble gases are very important to
understand in chemistry. It is the full outer shell that makes them so stable and other elements
have ways of interacting to become more stable like this group.
Transition Metals: (Columns 3-12) These are the metals in the middle of the table, they are all
malleable, ductile, and good conductors. They all have complex arrangements of electrons that
are best described with the quantum model of the atom. There is a wide range of properties in
this group. This is not a true family since it is so big but there are relations down the columns.
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Chapter 3
Compounds
All elements that are not noble gases have to try and find ways to become more stable like the
noble gases. There are two main ways to do this. As we have said before it is all about being
lazy, that ever is the easiest to do will happen most of the time.
1) Covalent Bonding: This happens with Non-metals only. Since non-metals are in a position to
need electrons to fill their outer shell, they have the option of sharing. The number of electrons
an element needs is the number of times it can share. For example Hydrogen needs 1 electron
to have 2 and have its outer shell full so it wants to share once and only once. Oxygen needs 2
electrons to have 8 in its outer shell so it wants to share a total of twice.
2) Ionic Bonding: This type of bonding has to take place between metals and non-metals. This
is taking and not the sharing that is explained with covalent bonding. Metals have only a few
electrons in the outer shell and if they lost them, they would have a new outer shell that would
be full. Non-metals don’t have enough electrons and if they gained some would fill their shell
and be stable. If an element loses electrons it will have more protons than electrons and have a
positive charge. If an element gains electrons it will have more electrons than protons and have
a negative charge. So Metals make positive ions and Non-metals make negative ions.
For example: Lithium has 1 electron in the outer shell, if it lost 1 electron it would only have 2
total while still having 3 protons, so it would now be a +1 Lithium ion. On the other hand
Fluorine has 7 electrons in its outer shell, if it gained 1 electron it would now have a total of 10,
while still having only 9 protons. This would make it into a -1 Fluorine Ion.
Ions with positive and negative charges come together by their attraction to each other in
groups that cancel out their opposite charges. Na+ for example comes together with Cl- to give
the Ionic compound NaCl, the 1+ cancels out the 1-. If you have Mg2+ you would need two Clto cancel it out and you would have MgCl2.
You can also do the cross method where you put the charge on one down as the number of ions
on the other. In the example above the 2+ becomes the 2 in Cl2 and the 1- makes 1Mg
Naming Ionic compounds
All ionic compounds are named using the same set of rules.
1) Write the name of all the ions the same as the element name except for the last ion to be
named.
2) If it is an elemental ion like the ion of Sulfur then you chop off the end and add -ide to it. For
example the ion of Sulfur becomes Sulfide
3) If the ion is a polyatomic ion (also called complex ions) then it keeps its name because that is
its ionic name anyway.
Examples: An ionic compound of Sodium and Chlorine would be called Sodium Chloride.
An ionic compound of Magnesium and Oxygen would be called Magnesium Oxide.
(Polyatomic example) An ionic compound between Lithium and the Sulfate ion would be called
Lithium Sulfate.
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Naming Covalent compounds
The naming of covalent compounds is similar to Ionic with one main difference. You still use the
full name of the first elements and chop off the ending and add -ide for the last. However you
add a prefix to each elment to tell you how many of each you have. The only exception is that
you dont the prefix Mono on the first element.
You use the following prefixes.
1=Mono 2=Di
3=Tri
4=Tetra 5=Penta
6=Hexa 7=Hepta 8=Octa 9=Nona 10=Deca
For example CO2 we know is called Carbon Dioxide. No prefix goes on the Carbon is because it
is first and it is only one carbon. There are two Oxygens so we need the Di- prefix and the -ide
ending because it is last.
C3H8 is Tricarbon Octahydride because of having 3 Carbons and 8 Hydrogens.
Physical and Chemical change
A physical change is a change in appearance only, the chemical structure of the material does
not change. This can be changes like Melting, Freezing, Evaporating ( These are changes of
state ). It can be a change of shape, like a log becoming sawdust. A substance can also
dissolve in another, it may look like is disappears but it is just mixed in with each other.
A chemical change involves the creation of one or more new chemicals. This will involve the
breaking of bonds and the creation of new bonds between the atoms. Things rusting is a great
example of a chemical change. So is the ripening of fruit and when things burn.
There are several indicators of a chemical change taking place.
1) Color change: if you combine two chemicals and there is a color change it is a good indicator
of a chemical change.
2) Heat, Light, or sound: All these are forms of energy. So if energy is given off or absorbed in
the case of heat and light then there has been a chemical change.
3) Bubbles of gas are given off: In a solution if a gas is produced then it is often a sign of a
chemical reaction.
4) A precipitate is formed: If you put two solutions together and a solid is formed and settles to
the bottom of the vessel, then a chemical change has taken place.
5) The process is difficult to reverse: Like with burning a log, it is difficult or impossible to put
the log back together. This can be an indicator of a chemical change.
The last of the material for this unit is the STSE on plastics or soaps. We may do the soap
activity.